<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>{1}</title>
    <style>
        canvas {
            border: 1px solid black;
        }
    </style>
</head>
<body>
<canvas width="600" height="400" id="cas"></canvas>
</body>
<script>
    var cas = document.getElementById('cas');

    var ctx = cas.getContext('2d');


</script>
</html>